Injection molding is a widespread method for creating plastic goods. A mold is created with a cavity identical to an original blank of the object to be reproduced. The mold is then held to the nozzle of an injection molding machine. The injection molding machine uses a screw to plasticize plastic pellets and convey a specified amount of plastic into an accumulation area downstream of the screw. The screw then translates forward, pushing the plastic shot through an injection nozzle and into the mold. After injection, the screw rotates, conveying material for a second shot into the accumulation area. This later process is known as recovery.
After injection, in hot runner molds, plastic can drool into the mold cavity, causing an imperfection on the following part. Therefore a need exists for a shut-off valve which immediately stops the flow of plastic through the nozzle once the mold is filled. Further, there is a need for a shut-off valve which can be attached downstream of at least two injection units to allow for co-injection of a mold.